I'll be honest, as a Guild Leader, people with that kind of attitude are the ones we don't want in the Guild. Hell, I know even some hardcore raiding guilds wouldn't want someone with an attitude like that in their guild.

Unless you're planning on selling gold, if you're only looking to make profit then you're going to find yourself unsubscribing very soon. Fact is, WoW is an MMO, which means you do have to have some sort of interaction with others, whether it be to buy or sell mats for professions, finding a raid group, or various other things which you will inevitably need help with.

If you're just looking to play by yourself, then play a single player RPG. If not, then stop worrying about profit and get involved with a Guild for the community aspect.

You can make close to 20k just from leveling a toon from 1-90. I have 11 toons on my main server, 2 90's, 4 85's, 4 lowbies, and 1 bank alt. I recently gathered up the balls to level a toon to 85 to make the grind to 90 a little less daunting. I was pleasantly surprised by the leveling speed changes from 1-85. You can seriously knock out close to 10 levels a day without breaking your back. So my suggestion really is, if you're looking for profit, level a fresh toon from 1-90, and sell all the green boe's and important mats (gems, cloth, cooking ingredients, etc.). You should wind up with about 15-20k from leveling alone, and 5-10k from selling anything profitable from leveling.

Dont look for popular guilds, look for guild that is for you.
make sure which kind of player are you (Hardocore, casual, PvPer, AH player, ect....) and try to find guild that will suit that, you cant have any benefit from guild that just isnt your type (and they will probably see that too, if you manage to get in).
If you dont speak english well for fluent understanding try to find polish speaking guild (a lot of them is out there, use WoWprogress.com to help finding them)
If you decide what player you are and find guild you wish to aply take time to fill the aplication, the first impression of you is super important and will decide 90% of all things unless you have superb logs/performance or reputation. That include the discussion with recruiter/guild after the aplication is posted, even the best aplication can be ruined after a few posts of bad attitude.
After you get accepted to the guild try to fit in the community as fast as possible (dont overdo it, just be friendly and helpfull).
Make sure you have everything required for task you are up to (consumables in raiding guild, time you agreed you have for PvP/Raid, Addons the guid require, ect...)

the rest is in your hands but this is a good start, have fun in WoW and your future guid. The guild should the backbone of the gameplay, sadly its not the case anymore.

are you sure where talking about the same game? because guilds don't offer discounts on timecards.(unless some1 in the guild does but thats probebly not what he ment)
guilds in world of warcraft offer benefits ingame. like extra exp. more hp/jp per kill. discount on vendors etc